Beverage preparation machines are well known in the food science and consumer goods area. Such machines allow a consumer to prepare at home a given type of beverage, for instance a coffee-based beverage, e.g. an espresso or a brew-like coffee cup.
Today, most beverage preparation machines for in-home beverage preparation comprise a system made of a machine which can accommodate portioned ingredients for the preparation of the beverage. Such portions can be soft pods or pads, or sachets, but more and more systems use semi-rigid or rigid portions such as rigid pods or capsules. In the following, it will be considered that the beverage machine of the invention is a beverage preparation machine working a rigid capsule.
The machine comprises a receptacle for accommodating said capsule and a fluid injection system for injecting a fluid, preferably water, under pressure into said capsule. Water injected under pressure in the capsule, for the preparation of a coffee beverage according to the present invention, is preferably hot, that is to say at a temperature above 70° C. However, in some particular instances, it might also be at ambient temperature. The pressure inside the capsule chamber during extraction and/or dissolution of the capsule contents is typically about 1 to 6 bar for dissolution products, 2 to 12 bar for extraction of roast and ground coffee. Such a preparation process differs a lot from the so-called “brewing” process of beverage preparation particularly for tea and coffee, in that brewing involves a long time of infusion of the ingredient by a fluid (e.g. hot water), whereas the beverage preparation process allows a consumer to prepare a beverage, for instance coffee within a few seconds.
The principle of extracting, infusing, and/or dissolving the contents of a closed capsule under pressure is known and consists typically of confining the capsule in a receptacle of a machine, injecting a quantity of pressurized water into the capsule, generally after piercing a face of the capsule with a piercing injection element such as a fluid injection needle mounted on the machine, so as to create a pressurized environment inside the capsule either to extract the substance or dissolve it, and then release the extracted substance or the dissolved substance through the capsule. Capsules allowing the application of this principle have already been described for example in applicant's European patent n° EP 1 472 156 B1, and in EP 1 784 344 B1.
Machines allowing the application of this principle have already been described for example in patents CH 605 293 and EP 242 556. According to these documents, the machine comprises a receptacle for the capsule and a perforation and injection element made in the form of a hollow needle comprising in its distal region one or more liquid injection orifices. The needle has a dual function in that it opens the top portion of the capsule on the one hand, and that it forms the water inlet channel into the capsule on the other hand.
The machine further comprises a fluid tank—in most cases this fluid is water—for storing the fluid that is used to dissolve and/or infuse and/or extract under pressure the ingredient(s) contained in the capsule. The machine comprises a heating element such as a boiler or a heat exchanger, which is able to warm up the water used therein to working temperatures (classically temperatures up to 80-90° C.). Finally, the machine comprises a pump element for circulating the water from the tank to the capsule, optionally though the heating element. The way the water circulates within the machine is selected via a selecting valve means, such as for instance a peristaltic valve of the type described in applicant's European patent application EP 2162653 A1.
When the beverage to be prepared is coffee, one interesting way to prepare the said coffee is to provide the consumer with a capsule containing roast and ground coffee powder, which is to be extracted with hot water injected therein.
Capsules have been developed for such an application, which are described and claimed in applicant's European patent EP 1 784 344 B1, or in European patent application EP 2 062 831.
In short, such capsules comprise typically:                a hollow body and an injection wall which is impermeable to liquids and to air and which is attached to the body and adapted to be punctured by e.g. an injection needle of the machine,        a chamber containing a bed of roast and ground coffee to be extracted,        an aluminum membrane disposed at the bottom end of the capsule, closing the said capsule, for retaining the internal pressure in the chamber, the said membrane being associated with piercing means for piercing dispensing holes in the said aluminum membrane when said internal pressure inside the chamber reaches a certain pre-determined value,        optionally, means configured to break the jet of fluid so as to reduce the speed of the jet of fluid injected into the capsule and distribute the fluid across the bed of substance at a reduced speed.        
Beverage preparation machines as described above are usually designed to accept a variety of different types of capsules, so as to allow a consumer to select in a wide range of products which beverage types she/he likes.
Depending on the type of beverage is prepared, preparation parameters may vary, for instance: delivery volume in cup, temperature of the fluid circulating through the capsule or pod, pressure of the fluid inside the capsule during preparation.
In many machines that are present on the market today, these preparation parameters are selected manually by the consumer, or some of them are fixed, and cannot be varied, which is a clear limitation in the level of product quality that can be achieved. For instance, the consumer can chose which volume of beverage he likes in the cup, but there is no possibility to vary the pressure or temperature of the fluid circulating through the capsule. In that case, fluid pressure and temperature are substantially the same for an espresso coffee, for a tea-based beverage, or for a chocolate-based drink, although it is known that such parameters like fluid pressure and temperature should be adapted to the type of ingredient which needs to be infused, extracted under pressure, or dissolved.
To solve this issue, some beverage preparation systems have been developed, whereby the capsule type is detected automatically by the machine, such that the latter automatically adapts its settings, hence the preparation parameters, as a function of the type of ingredient contained in each different type of capsule/pod.
WO 2005/044067 A1 discloses an apparatus for determining the traceability of the contents of a container as well as the origin of said container, wherein information provided on said container can be read using an optical and/or magnetic reader but is invisible to the naked eye. Said container comprises a pierceable upper portion for injecting a liquid into the container, and a pressure-pierceable lower diaphragm for discharging the liquid flavored by the contents of the container. The apparatus includes an optical and/or magnetic reader for reading said information off a container placed inside the apparatus, a microprocessor for encrypting and decrypting, processing, comparing, approving or rejecting and storing the information read off a container, and for selectively initiating or not initiating an operative cycle which includes piercing the upper portion of the container and injecting the liquid, as well as for storing said information to ensure readiness for the initiation of a fresh cycle.
One type of detection is based on recognition by the machine of the shape of the capsule. In this case, each capsule type differs from other capsule types by a shape-specific element disposed at a location at the surface of said capsule, which corresponds to a shape sensor of the machine when said capsule is inserted in the latter. This detection system, although efficient, is expensive in that it requires different manufacturing lines to produce each different type of capsule: it is not possible to standardize the capsule body. Moreover, it requires a contact between the capsule and the shape sensor of the machine, such that the functional dimensions between capsule and machine have to be very carefully monitored and set up in the factory, which adds to the manufacturing difficulty and expenses.
Another type of detection is based on magnetic recognition by the machine, of a magnetic code that is present in the capsule. Such a magnetic code can take the form of a magnetic band that is printed, attached to, or otherwise integrated into the capsule material. Such a detection type allows a great variety of codes, so that an important variety of different capsule types can be managed. However, it requires an important investment in machines to produce the magnetic code inside the capsules, and the magnetic sensor inside the machine is rather expensive, which is not compatible with a reasonable manufacturing cost for consumer goods such as beverage preparation machines, whose price must remain as low as possible.
Yet another type of detection that can be used is colour recognition of at least one part of the capsule by a colour sensor disposed in the machine. Each colour, or colour combination—in case various parts of the machine having different colours are detected—codes for a type of ingredient contained therein. Although this solution is an interesting way to allow an automatic detection of the capsule, it remains quite expensive, especially the colour sensors. Moreover, the colour sensors are very sensitive to ambient light and require that the detection be made inside the machine, or preferably, that a light emitting source—for instance a light emitting diode be used to give a standard light colour measure to the sensor before the latter detects the capsule colour. The true capsule colour is in that case a differential measurement obtained by processing the two measures. Also the detection in that case is precise and reproducible, it remains an expensive way of detection.
Yet another type of detection that is proposed is called “RFID” for “Radio Frequency Identification”. This consists in placing a small chip into the capsule, which emits a specific radio frequency, that is detected by an RFID sensor placed in the machine. Each given frequency codes for a capsule type. Although this technology is reliable and efficient, it is too expensive compared to other available techniques.
Last but not least, detection of the capsule type can be performed by barcode recognition. In this case, a one-dimensional, or two-dimensional barcode is printed on the surface of the capsule, which is read by a barcode reader disposed in the beverage preparation machine. This technique is very much used, as it is reliable, efficient, and rather cheap. However, it requires printing on the capsule, preferably on a flat surface of the capsule, i.e. on the top side of the latter. However, for aesthetic reasons, or because other information is already printed on said capsule—for instance brand name, logo, picture, ingredient information, or other consumer information—, printing the capsule with a barcode can be difficult.
Additionally, in many instances where the capsule has the shape of a frustoconical cylinder, closed at its top by a membrane, it is necessary to print the barcode in a central position of the top side (i.e. top membrane) of the capsule, and said barcode needs to be a 2D barcode, so that the latter can be read by the machine, whatever the rotational position of the capsule inside the machine (relative to its vertical axis). Applicant's European patent applications EP AN 10151030.3 and EP AN 10151020.4 disclose such a centered 2D barcode on a capsule for recognition.
A problem with 1D and 2D barcodes is that the capsule needs to be oriented relative to the reader so that the latter can read the code properly. Alternatively, existing machines that can detect and read the code whatever the orientation of the capsule along its vertical axis, necessarily require powerful, hence very expensive, processors to calculate the code from an image that is recorded by a sensor. As can be understood, the existing technology related to 1D or 2D barcodes comprises major drawbacks. Last but not least, with these technologies, the barcode reader has to be placed at a certain minimal distance from the capsule surface that contains the code, so as to be able to read the latter. This adds to the difficulty in implementing such technologies, due to the fact that beverage preparation machines have to be as compact as possible, especially when they are designed and sold for in-home use.
In order to solve the barcode printing issue at the surface of the capsule, invisible ink barcodes have been developed, which allow a barcode to be printed at a location of the capsule, e.g. centered across the top membrane of the capsule, where a visible printing is already present. The invisible barcode is detected by illuminating the same with a specific light wavelength, for instance a UV or infrared light source disposed within the beverage preparation machine together with the barcode reader. Such a technique however is expensive due to the equipment that is required inside the machine, and also due to the rather high cost of invisible ink compared to a classic, visible, ink.
As can be seen, although various solutions have been proposed to allow automatic detection of the capsule by the beverage preparation machine, there is still a need for a detection system which is inexpensive, efficient, reliable, which allows to code for a large amount of data so that a wide selection of different capsule types can be coded and recognized by the machine, and last but not least, which does not require a lot of space at the surface of the capsule, so as not to impair the capsule aesthetics, or otherwise leaves sufficient surface in the centre of the capsule sides for printing logos, brand names, and ingredient information.